Cellular wireless networks include a large number of individual base stations or cells that provide high capacity wireless services over large coverage areas such as cities, surrounding residential areas, highway corridors and rural areas. Maximizing the capacity of such networks while utilizing a limited licensed radio frequency spectrum mandates a reuse of time and frequency channel resources throughout the cells in the network.
Third and fourth generation commercial wireless network technologies (3G and 4G) maximize system performance via high levels of time, coding and frequency channel reuse, whereby most if not all cells in a network are provisioned to utilize the same radio frequency spectrum. This can lead to high levels of interference and poor performance particularly for users operating at the overlapping boundary regions between neighboring cells. Because of the high levels of interference, network performance is substantially degraded when compared to a case where there is no interference.
Interference reduction techniques have been developed that can reduce the levels of interference throughout the network. Some examples of these interference reduction techniques include Fractional Frequency Reuse (FFR), Inter Cell Interference Coordination (ICIC) and Coordinated Power Scheduling. Operators that plan make use of one or more of these interference reduction techniques would like to be able to understand the performance benefits that these techniques provide to their networks.
There are several metrics that can be looked at before and after an interference reduction scheme has been deployed that can provide a measure of the performance benefits of the interference reduction schemes. Some examples of the metrics are network throughput, per-cell throughput, cell edge throughput, per-cell spectral efficiency, and cell edge spectral efficiency.
It can be useful to compare the performance of a network that utilizes an interference reduction scheme with a network in which no interference is present. This provides a measure of how well an interference reduction scheme performs against an ideal case in which no interference is present in the network and the radio links in the network are limited only by background thermal noise. Such a case would provide performance equivalent to each link operating on a different frequency to all near neighbor links.
The performance benefits of an interference reduction scheme could be measured by periodically disabling the interference reduction scheme globally across the network and making measurements of the performance without the interference reduction scheme enabled. However, network operators would usually prefer to not disrupt the operation of the network and instead be able to make a performance comparison without disabling the interference reduction scheme.